The circuit shown is used as a condition circuit for capacitive sensor, Assume RA-100k and RB=50kn, VC=5 V and C is used as level sensor where C=20pF if the tank is empty and 200PF if the tanks is full. a. Find the change in the output frequency f b. Mention two ways to make the duty cycle almost 50% c. What extra circuit you need if a DC output voltage is required? d. If the maximum frequency of the 555 timer is 1MHz, what is the minimum capacitance we can use in this circuit? i Vc RA RB WWW ww 6 8 555 Timer 21 3 f